NEWTOWN, Pa.--(BUSINESS WIRE)--CollaGenex Pharmaceuticals, Inc. (NASDAQ:CGPI) today announced that it has discontinued treatment of all enrolled patients participating in the 40 mg cohort of its Phase II dose-finding study of incyclinide for the treatment of acne. On May 2, 2007, CollaGenex announced that it had suspended enrollment of new patients in this cohort pending investigation of apparent significant photo-toxicity in one patient. Subsequently, the Company has learned of another case of apparent photo-toxicity and has discontinued treatment of all patients in this cohort. Following further investigation, CollaGenex will meet with the FDA to discuss the ongoing development program for incyclinide.